Blasting cartridge and charge



May 8, 1934. A. c. SCOTT BLASTING CARTRIDGE AND CHARGE Filed Feb. 25. 1931 INVENTOR am/MM Patented May 8, 1934 UNITED STATES PATENT OFFICE r 1,957,733 BLASTING CARTRIDGE AND CHARGE Application February 25, 1931, Serial No. 518,296

r In Great BritainMarch 4, 1930 8 Claims.

This invention comprises improvements in and relating to blasting cartridges and charges. It is an object ofthis invention to provide an improved form of blasting explosive for use, for

example, in coal mines which is characterized by a high degree of safety from risk when exploded in a dangerous atmosphere such as that of a fiery mine and which at the same time is safe somev of which are unsafe in storage and others of which are unsatisfactory in combustion when in use.

According to the present invention, a blasting cartridge of the type comprising a 'cylinder' charged with a compressed inert gas that is to say a non-supporter of combustion such as carbon dioxide, is provided with a'heating element, the essential constituents ofwhich are potassium perchlorate (K0104) or like oxygen-carrying crystalline body, the crystals of which are intermingled and coated with a. proportion of a resinous body. Preferably the resinous body employed is a phenol formaldehyde condensation product such, for example, as that which is known in commerce under the registered trademark Bakelite as resin A or the resin sold as E10 resin.

One very advantageous use of the heating element of the present invention is in connection with blasting cartridges of the type shown in United States Patent No. 1,805,541, granted 49 to Dent Ferrell and Arthur W. Helmholtz, and

for purposes of illustration the present invention is herein shown as applied to a cartridge of this general type.

The following is a description by way of example of a particular form ofa blasting cartridge,

in which resin is employed as a fuel, constructed in accordance with this invention. In this example the heating element consists of potassium perchlorate (KC104) 84%, and E10 resin 50 in the solidified state, 16%.

The perchlorate is finely powdered, and the resin is admixed therewith in the sy py stage apart from any extraneous solvent. This material is pressed into cakes, hardened by heat and then broken into granules. The size of the granules is preferably such as would pass through a screen having 30 meshes to the lineal inch but will be retained upon a screen having 120 meshes to the lineal inch, but finer powder or unsifted material can be used if desired. The perchlorate powder prior to incorporation with the resin has avery fine-grain of the order of that which would pass a screen having 200 meshes to the lineal inch;

This heating mixture is introduced into a tubular container made of kraft paper with pressed steel end-caps which act as electric terminals. There is packed in the cartridge a capsule of a standard electric igniting fuse. The igniting compound is electrically connected to w the terminals.

The drawings are views in longitudinal section of a blasting cartidge of the type hereinabove referred to and showing the improved heating mixture of the present invention applied thereto. Referring to the drawings, it will be noted that the present invention is disclosed as embodied in a cartridge comprising a steel casing '10 which maybe, for example, 30 inches in length and about 2 inches in diameter and 89 having a rupturable sealing disc 11 and a directing cap 12 at the discharge end. The rupturable steel sealing disc is of such a strength as to be capable of expulsion into cap 12 under a pressure less than that which would suffice to burst the walls of the steel container itself. Means 13 are provided'for establishing an electrical connection for the heating element and for introducing carbon dioxide into the interior 14 of the cartridge. The carbon dioxide is introduced 90 in the form of snow to the amount of 3 pounds. The amount of heating mixture for this quantity of CO2 is about 4 ounces, and for larger or smaller quantities pro rata. The cartridge construction will not herein be described in detail inasmuch as it is substantially the same as that shown in the United States patent above re' ferred to.

The heat producing unit 15 comprises a tubular container made of kraft paper, in which the heating mixture is carried and is adapted to be inserted in. the position shown in the drawings. The tubular container 15 carries an electrical connection 16 at one end which makes contact with a rupturable sealing disc 11 and an electrical connection 17 at the opposite end thereof, in contact with the plate 18 constituting the other terminal for the electrical circuit. A capsule of a standard electric igniting fuse is packed in the heating mixture contained in the unit and is present 'degree to blow out the thereof.

walls of the heatingelement and this, together with the intense heat of combustion orexplosion of the mixture acting upon the CO2, raises the pressure within the container to a sufiicient The result is an explosion, any flame of which is completely screened from surrounding combustible gases by the carbon dioxide present in the container. The efiect of such an explosion is greatly enhanced according to the invention by the uniformity of combustion of the'heating element and the intensity of the. heat produced, while at the same time the material of which the heating mixture is composed is capable of storage over lengthy periods without deterioration or risk of self-ignition.

The rate of combustion of the heating compound in the above example can be regulated by varying the size of grain and also the rate and heat of combustion of'the heating element can be regulated within Wide limits by varying the constituents, using in combination various mixtures of chlorates, and perchlorates and the like and this without rendering the charge subject to undesired alterations during storage. This capability of varying the characteristics of the charge is a valuable feature of the invention.

I claim:-:

'1. A blasting cartridge of the type comprising a cylinder charged with a compressed inert gas, provided with a heating element the essential constituents of which are potassium perchlometal disc at the end,

rate. (K0104) and aresinous body intermingled with and coated upon the crystals.

2. A blasting cartridge as claimed in claim 1. wherein the resinous body is a phenol formaldehyde condensation product.

3. A blasting cartridge'as claimed in claim 1, wherein the heating element consists of approximately 84% of potassium perchlorate and approximately 16% of phenol formaldehyde resin in the solidified state.

4. A blasting cartridge as claimed in claim 1, wherein the heating element is in the form of granules such 'as would pass through a screen having 30 meshes to the lineal inch but will be retained upon a screen having 120 meshes to the lineal inch.

5. A blasting cartridge as claimed in claim 1, wherein the potassium perchlorate, prior to incorporation with the resinous body, is in the form of a powder such as would pass a screen having 200 meshes to the lineal inch.

6. A blasting cartridge comprising-in combination a cylinder charged with a compressed inert gas and a heating element therein, the essential constituents of which are an oxygen-carrying 100 crystalline body and a resinous body uniformly distributed therethrough.

7 A blasting cartridge comprising in combination a cylinder charged with a compressed inert gas and a heating element therein, the essential 105 constituents of which are an oxygen-carrying crystalline body and a resinous body'insoluble under compressed carbon dioxide.

8. A blasting cartridge comprising in combination a cylinder charged with a compressed 1m inert gas and a heating element therein, the essential constituents of which are an oxygencarrying crystalline body and a phenol formaldehyde condensation product.

ALEXANDER CRUICKSHANK SCOTT. 115 

